﻿using System.Collections.Generic;
using System.Web;
using System.Web.Script.Serialization;
using System.Data;
using System;

/// <summary>
/// JSON帮助类
/// </summary>
public class JSONHelper
{
    /// <summary>
    /// 对象转JSON
    /// </summary>
    /// <param name="obj">对象</param>
    /// <returns>JSON格式的字符串</returns>
    public static string ObjectToJSON(object obj)
    {
        JavaScriptSerializer jss = new JavaScriptSerializer();
        try
        {

            return jss.Serialize(obj);
        }
        catch (Exception ex)
        {

            throw new Exception("JSONHelper.ObjectToJSON(): " + ex.Message);
        }
    }

    /// <summary>
    /// 数据表转键值对集合
    /// 把DataTable转成 List集合, 存每一行
    /// 集合中放的是键值对字典,存每一列
    /// </summary>
    /// <param name="dt">数据表</param>
    /// <returns>哈希表数组</returns>
    public static List<Dictionary<string, object>> DataTableToList(DataTable dt)
    {
        List<Dictionary<string, object>> list
             = new List<Dictionary<string, object>>();

        foreach (DataRow dr in dt.Rows)
        {
            Dictionary<string, object> dic = new Dictionary<string, object>();
            foreach (DataColumn dc in dt.Columns)
            {
                dic.Add(dc.ColumnName, dr[dc.ColumnName]);
            }
            list.Add(dic);
        }
        return list;
    }

    /// <summary>
    /// 数据集转键值对数组字典
    /// </summary>
    /// <param name="dataSet">数据集</param>
    /// <returns>键值对数组字典</returns>
    public static Dictionary<string, List<Dictionary<string, object>>> DataSetToDic(DataSet ds)
    {
        Dictionary<string, List<Dictionary<string, object>>> result = new Dictionary<string, List<Dictionary<string, object>>>();

        foreach (DataTable dt in ds.Tables)
            result.Add(dt.TableName, DataTableToList(dt));

        return result;
    }

    /// <summary>
    /// 数据表转JSON
    /// </summary>
    /// <param name="dataTable">数据表</param>
    /// <returns>JSON字符串</returns>
    public static string DataTableToJSON(DataTable dt)
    {
        return ObjectToJSON(DataTableToList(dt));
    }

    /// <summary>
    /// JSON文本转对象,泛型方法
    /// </summary>
    /// <typeparam name="T">类型</typeparam>
    /// <param name="jsonText">JSON文本</param>
    /// <returns>指定类型的对象</returns>
    public static T JSONToObject<T>(string jsonText)
    {
        JavaScriptSerializer jss = new JavaScriptSerializer();
        try
        {
            return jss.Deserialize<T>(jsonText);
        }
        catch (Exception ex)
        {
            throw new Exception("JSONHelper.JSONToObject(): " + ex.Message);
        }
    }

    /// <summary>
    /// 将JSON文本转换为数据表数据
    /// </summary>
    /// <param name="jsonText">JSON文本</param>
    /// <returns>数据表字典</returns>
    public static Dictionary<string, List<Dictionary<string, object>>> TablesDataFromJSON(string jsonText)
    {
        return JSONToObject<Dictionary<string, List<Dictionary<string, object>>>>(jsonText);
    }

    /// <summary>
    /// 将JSON文本转换成数据行
    /// </summary>
    /// <param name="jsonText">JSON文本</param>
    /// <returns>数据行的字典</returns>
    public static Dictionary<string, object> DataRowFromJSON(string jsonText)
    {
        return JSONToObject<Dictionary<string, object>>(jsonText);
    }
}
